I. Field of the Invention
The present invention is directed toward data terminal devices and more particularly to a keyboard for use in such terminal devices which is compact in construction while still providing lead-through operation of the keys.
II. Description of the Prior Art
In order to reduce the overall cost of terminal devices, low cost membrane-type keyboards have been developed for use with terminal devices. This type of keyboard includes a plurality of substrates assembled to provide a compact structure with the top substrate having portions forming the keys of the keyboard. This type of keyboard is well suited where the keyboard is required to have a large number of keys. Where the circuit elements associated with the keyboard are small in structure and the number of keys are limited such as found in ten key keyboards, such circuit elements are easily secured to the rear surface of the keyboard. When the keyboard has a large number of key positions and the circuit elements are large, such as in the case of capacitors or other types of large circuit elements, it has been the procedure to locate these elements adjacent the keyboard within the terminal. The keyboard is connected to these circuit elements by the use of a ribbon cable. This type of construction lends itself to operating problems such as EMC interference due to the required use of the ribbon cable while also increasing the cost of the keyboard. Because of the membrane-type contstruction of the keyboard, it has been difficult to provide a lighting arrangement for lead-through operation of the keyboard.